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Patented Oct. 26, 1943 v r i I TENT OFFICE PROCESSES FOR THE PRODUCTION OF Z-AMINOPYRIMIDINE Edmond T. Tisza and Bernard F. Duesel, Yonkers, and Harris L. Friedman, New York, N. Y., assignors to Nepera Chemical 00., Inc, Yonkers, N. Y., a corporation of New York No Drawing. Application September 25, 1942,

Serial No.4 59,8'74

Claims.

Our invention relates to processes for the production of aminopyrimidines and refers particularly to processes for the production of 2-aminopyrimidine.

Several processes have been suggested for the production of Z-aminopyrimidine, which is an intermediate employed in the production of sulfanilamidopyrimidine, an important therapeutic agent.

One of the proposed processes for the producticn of 2-aminopyrimidine comprises the reduction of 2-amino-4-chloropyrimidine, which process consists in reducing the 2-amino-4-chloropyrimidine by means of zinc in aneutral or alkaline solution, evaporating the solution to a small volume, salting out with an alkali, preferably potassium hydroxide, and collecting the formed 2-aminopyrimidine.

The amount of 2-aminopyrimidine produced by the above described process, however, is far below the theoretical quantity that should be produced, and which is, in fact only forty per cent to fifty per cent of the theoretical quantity.

Our invention is directed to processes for the production of Z-amino-pyrimidine from Z-aminol-chloropyrimidine in acid solution.

The steps of our processes for the production of Z-aminopyrimidine from Z-amino-l-chloropyrimidine comprise reducing the 2-amino-4- chloropyrimidine in an acid solution by means of zinc, adding a zinc salt to the thus produced mixture, evaporating to precipitate the zinc double salt of Z-aminopyrirnidine thus produced and producing the Z-aminopyrimidine by the 1:."

addition of an alkali. We have found that the zinc double salt of Z-aminopyrimidine thus produced consists of one mole of the zinc compound and one mole 2-aminopyrimidine.

In the following of our processes We prefer to employ zinc and acetic acid or hydrochloric acid, and potassium hydroxide or sodium hydroxide and zinc chloride but other acids and alkalies, previously used for reactions similar to those described may be employed.

We have found that the most satisfactory yields of 2-aminopyrimidine may be obtained by favorable for the acid reduction step, but we do not limit ourselves to this particular acid strength.

We give the following as examplesof our process 7 Example I 3 grams crude (88%) 2-amin0-4-c'n1oropyrimidine were dissolved in 250 cc. hot water. After the solution cooled down to C., 10 gms. zinc dust and 1 cc. 50% acetic acid were added under constant stirring. The stirring was continued and the temperature of the mixture was kept constantly at 70-73" C. After about one half hour '1 cc. of 50% acetic acid was added. The stirring was continued for four anda half hours, and

then the solution wa filtered. 1.3 grams zinc chloride were added and evaporated down to a yield.

Example II 2.5 grams 2-amino-l-chloropyrimidine (96% pure) were dissolved in 250 cc. hot water, cooled to 60 and reduced with zinc dust and acetic acid as described in Example I, keeping the temperature at 60-63 C. and stirring for 2 hours. The solution was worked up as in Example I. 1.32 grams of the product were obtained which represents yield.

Example III dust and 1 cc. dilute (about 18%) hydrochloric our process by employing 2-aminoA-chloropyrimidine, reducing with zinc in "an acid solution, adding one mole, or slightly more than one mole of a zinc chloride and adding sufiicient alkali to convert the thus produced zinc chloride double salt into alkali .zincate and the Z-aminopyrimidine.

We have found that pI-I6.1 is generally most acid were added under stirring. The mixture was kept under constant stirring at l0-73 C. for about 2 hours. After filtering, the solution was worked up as in Example I. 1.22 grams of the product were obtained, which represents 67% yield.

Ihe benzene mentioned in the above Examples may be substituted by other solvents for 2-aminopyrimidine which are not miscible with water, among which are toluene, xylene, chlorinated hydrocarbon such as chloroform, carbontetrachloride, etc.

We do not limit ourselves to the specifically mentioned times, temperatures, quantities, chemicals, or steps of procedure as these are given simply to clearly describe our invention as set forth in our specifications and claims and they may be varied without going beyond the scope of our invention.

What we claim is:

1. In a process for the production of Z-aminopyrimidine the steps which comprise the reduction of 2-amino-4-chloropyrimidine in an acid solution and adding zinc chloride forming a double salt consisting of one mole of zinc chloride and one mole of 2-aminopyrimidine.

2. In a process for the production of 2-aminopyrimidine the steps which comprise the reduction of 2-amino-4-chloropyrimidine in an acetic acid solution and adding zinc chloride forming.

a double salt consisting of one mole of zinc ,chloride and one mole of Z-aminopyrimidine.

3. In a process for the production of 2-aminopyrimidine the steps which comprise the reducpyrimidine the step which comprises reacting upon. the zinc double salt consisting of one mole of zinc chloride and one mole of 2-aminopyrimidine with potassium hydroxide.

6. In a process for the production of 2-aminopyrimidine the step which comprise reacting upon the zinc double salt consisting of one mole of zinc chloride and one mole of Z-aniinopyrimidine with sodium hydroxide.

'7. A process for producing Z-aminopyrimidine which comprises reducing 2-amino-4-chloropyrimidinc in an acid solution, adding zinc chloride formin a compound consisting of one mole of zinc chloride and one mole of Z-aminopyrimidine, evaporating to a smaller volume, separating the precipitated said zinc chloride double salt from the solution, dissolving said precipitate, adding an alkali, and separating the precipitated 2-aminopyrimidine from the solution.

8. A process for producing Z-aminopyrimidine which comprises reducing 2-amino-4-chloropyrimidine in an acetic acid solution, addingzinc chloride forming a compound consisting of one 5' mole of zinc chloride and one mole of 2-aminopyrimidine, evaporating to a smaller volume, separating the precipitated said zinc chloride double salt from the solution, dissolving said precipitate, adding an alkali, and separating the precipitated Z-aminopyrimidine from the solution.

9. A process for producing Z-aminopyrimidine which comprises reducing 2-amino-4-chloropy- 10. A process for p oducing 2-% py ne which comprises reducing 2-amino-d-chloropy-,v I

rimidine with zinc dust in the;' presence of an acid, filtering the dissolved, reduction product, 3

adding zinc chloride to the solution, evaporating to precipitate the zinc chloride double salt thus produced, adding an alkali thereto and separating the Z-aminopyrimidine therefrom.

11. A process for producing 2-aminopyrimidine which comprises reducing 2-amino-4-chloropyrirnidine with zinc dust in the presence of hydrochloric acid, filtering the dissolved reduction product, addin zinc chloride to the solution, evaporating to precipitate the zinc chloride double salt thus produced,'adding an alkali thereto and separating the Z-aminopyrimidine therefrom.

12. A process for producing 2-aminopyrimidine which comprises reducing Z-aminol-chlor'opyrimidine with zinc dust in thepresence .of acetic acid, filtering the dissolved reduction product, adding zinc chloride to the solution, evaporating to precipitate the zinc chloride double salt thus produced, adding an alkali thereto and separating the Z-aminopyrimidine therefrom.

13. A process for'producing 2-aminopyrimidine which comprises reducing 2-amin-o-4-chloropyrimidine with zinc dust in the presenceof an acid, filtering the dissolved reduction product,

adding zinc chloride to the solution, evaporating to precipitate the zinc chloride double saltthus produced, adding an alkali thereto .and sepa'ratingthe 2-aminopyrimidine therefrom by means of a volatile solvent. l

14. A process for producing 2-aminopyrlmidine which comprises reducing '2-'amino -4-'chloropyrimidine with Zinc dust in the presence of hydrochloric acid, filtering the dissolved reduction product, adding zinc chloride to thesolution, evaporating to precipitate the zinc chloride double} salt thus produced, adding. an alkali thereto and separating the Z-aminopyrimidine therefrom by means of a volatile solvent. Y 4

15. A process for producing Z-aminopyrimidine which comprises reducing 2-amino-4-chloropyrimidine with zinc dust in the presence of acetic acid, filtering the dissolved reduction product adding zinc chloride to the solution, evaporating to precipitate the zincchloride double salt thusj produced, adding an alkali thereto and separate ing the 2-aminopyrimidine therefrom, bymeans of a volatile solvent.-

EDMOND T- TISZA/ BERNARD F; DUESEL. HARRIS L. FRI MAN. 

